If anyone has an Android device or clients that may have one, I've developed a plugin and Android app that allows a user to easily switch their site themes. The plugin is called WP Theme Changrr Connector (http://wordpress.org/plugins/wp-theme-changrr-connector/). More information on the app can be found on the plugin page.
If there is enough interest in it, I may develop an app for iOS and provide a Multisite solution. Feel free to provide feedback and thoughts through the plugin page or the app. It's encouraged. Thank you for any interest.